The organic light-emitting diode element (hereinafter, also referred to as OLED element) has a problem with a gradual deterioration of the emission property, such as emission brightness and emission efficiency caused by the use thereof. Examples of the causes include organic matter denaturation and electrode oxidation, due to penetration of moisture or the like into the organic light-emitting diode element.
In order to prevent these problems, a technique for suppressing deterioration of the organic light-emitting diode element has been studied, by sealing the organic light-emitting diode element, thereby preventing moisture or the like from penetrating into the organic light-emitting diode element (see, for example, Patent Literature 1).
However, this technique needs a space for placing a getter for water removal as a sealing cover, and therefore has a problem with making it thinner. In order to solve this problem, a technique has been studied, which enables to making it thinner by blending a desiccant filler in a radiation curable resin (see, for example, Patent Literature 2).
However, regarding the sealant in which the desiccant filler is blended like the above-described technique, light permeability becomes low, because light is shield by the filler. This sealant can be used to seal the so-called bottom emission-type device in which an organic light-emitting layer is formed on a transparent substrate and light is taken out from the transparent substrate side. However, this sealant is not suitable for sealing the so-called top emission-type device in which sealing is performed so as to cover the upper portion of the organic light-emitting layer formed on a substrate and light is taken out from the sealed side. Further, in the case of using inorganic particles as a desiccant, there is a high risk that the inorganic particles themselves crush and destruct the OLED element under the pressure at the time of sealing. Further, in the case of using a water absorptive polymer, water absorption ability thereof is not enough.
In order to solve these problems, a technique has also been studied, which adds a moisture-reactive organometallic compound to a sealing resin (see, for example, Patent Literatures 3 to 5). In the case of adding an organometallic compound to the sealing resin, it is also required to make the organometallic compound and the sealing resin homogeneously compatible and to suppress migration of alcohol which is released from the organometallic compound.
However, in the technique which has been studied in the past in order to satisfy these requirements, it was necessary to make a degree of cross-linkage of the sealant cured material low, for example, by using a non-crosslinked material or a monoacrylate. As the result, a water vapor barrier property of these sealants was poor, and also flexibility thereof was not enough, and therefore bendability was not enough.